When I installed 18.04 I chose auto login, so I wouldn’t be bothered with a password. My computer is used at home, not in a public environment.
It starts up with auto login, but coming out of suspend/sleep/what_ever_it_is_called demands a password, exactly what I didn’t want.
I already discovered you have to have a password, else you can’t do software updates for example or drop into terminal mode and run any sudo command.
Thanks, Fred